Pen



FIG. 1 is an upper rear right perspective view of a pen showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a right side elevation view thereof, with the left side elevation view being a minor image of the right side elevation view;

FIG. 5 is an enlarged top plan view thereof; and,

FIG. 6 is an enlarged bottom plan view thereof.

The broken lines on the bottom in FIG. 6 are included for the purpose of showing a portion of the pen that forms no part of the claimed design. 

CLAIM The ornamental design for a pen, as shown and described. 